The long-term objective of this project is to develop methods that will enable the analysis of structural chromosome aberrations in interphase cells. The immediate goal is to detect and enumerate translocations by automated image analysis to detect very low frequencies of translocations against a background of normal cells. The Specific Aims of Phase I are 1) to develop an in vitro technique employing the products of mitotic cells and/or frog oocytes to condense the chromatin of unfixed interphase nuclei into whole chromosomes for enumeration of aberrations by fluorescence in situ hybridization with whole chromosome painting probes, 2) to produce high densities of such condensed chromosomes and/or nuclei on microscope slides to permit automated image analysis, 3) to modify existing dot.counting software for application to the automated image analysis of condensed chromosomes in interphase cells, 4) to quantify translocations in interphase cells by automated image analysis. The methodology developed from this project should be applicable to the detection of chromosome aberrations in tumor biopsies, and fine needle aspirates as well as the screening of potential mutagens/ carcinogens and radioprotectants. It is anticipated that kits containing these reagents for chromosome condensation could be ultimately marketed as research and clinical products. PROPOSED COMMERCIAL APPLICATION: Environmental mutagenesis; cancer early diagnosis and prognosis.